R. Alarcon - Physics Department, Arizona State University, Tempe

R. Alarcon
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Name
R. Alarcon
Affiliation
Physics Department, Arizona State University, Tempe
City
Tempe
Country
United States

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Nuclear Experiment (22)
 
Physics - Instrumentation and Detectors (6)
 
High Energy Physics - Experiment (4)
 
Physics - Accelerator Physics (3)
 
High Energy Physics - Phenomenology (1)
 
Nuclear Theory (1)
 
Computer Science - Digital Libraries (1)
 
Computer Science - Artificial Intelligence (1)
 
Quantum Physics (1)

Publications Authored By R. Alarcon

The standard model predicts that, in addition to a proton, an electron, and an antineutrino, a continuous spectrum of photons is emitted in the $\beta$ decay of the free neutron. We report on the RDK II experiment which measured the photon spectrum using two different detector arrays. An annular array of bismuth germanium oxide scintillators detected photons from 14 to 782~keV. Read More

Randomness is fundamental in quantum theory, with many philosophical and practical implications. In this paper we discuss the concept of algorithmic randomness, which provides a quantitative method to assess the Borel normality of a given sequence of numbers, a necessary condition for it to be considered random. We use Borel normality as a tool to investigate the randomness of ten sequences of bits generated from the differences between detection times of photon pairs generated by spontaneous parametric downconversion. Read More

We describe the current status of the DarkLight experiment at Jefferson Laboratory. DarkLight is motivated by the possibility that a dark photon in the mass range 10 to 100 MeV/c$^2$ could couple the dark sector to the Standard Model. DarkLight will precisely measure electron proton scattering using the 100 MeV electron beam of intensity 5 mA at the Jefferson Laboratory energy recovering linac incident on a windowless gas target of molecular hydrogen. Read More

Liquid hydrogen is a dense Bose fluid whose equilibrium properties are both calculable from first principles using various theoretical approaches and of interest for the understanding of a wide range of questions in many body physics. Unfortunately, the pair correlation function $g(r)$ inferred from neutron scattering measurements of the differential cross section $d\sigma \over d\Omega$ from different measurements reported in the literature are inconsistent. We have measured the energy dependence of the total cross section and the scattering cross section for slow neutrons with energies between 0. Read More

The OLYMPUS experiment was designed to measure the ratio between the positron-proton and electron-proton elastic scattering cross sections, with the goal of determining the contribution of two-photon exchange to the elastic cross section. Two-photon exchange might resolve the discrepancy between measurements of the proton form factor ratio, $\mu_p G^p_E/G^p_M$, made using polarization techniques and those made in unpolarized experiments. OLYMPUS operated on the DORIS storage ring at DESY, alternating between 2. Read More

We report on the measurement of optical isotope shifts for $^{38,39,42,44,46\text{-}51}$K relative to $^{47}$K from which changes in the nuclear mean square charge radii across the N=28 shell closure are deduced. The investigation was carried out by bunched-beam collinear laser spectroscopy at the CERN-ISOLDE radioactive ion-beam facility. Mean square charge radii are now known from $^{37}$K to $^{51}$K, covering all $\nu f_{7/2}$-shell as well as all $\nu p_{3/2}$-shell nuclei. Read More

2013Jul
Affiliations: 1Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 2Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 3Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 4Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 5Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 6Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 7Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 8Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 9Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 10Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 11Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 12Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 13Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 14Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 15Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 16Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 17Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 18Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 19Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 20Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 21Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 22Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 23Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 24Jefferson Lab, Newport News, VA USA, 25Jefferson Lab, Newport News, VA USA, 26Jefferson Lab, Newport News, VA USA, 27Jefferson Lab, Newport News, VA USA, 28Jefferson Lab, Newport News, VA USA, 29Jefferson Lab, Newport News, VA USA, 30Jefferson Lab, Newport News, VA USA, 31Jefferson Lab, Newport News, VA USA, 32Jefferson Lab, Newport News, VA USA, 33Jefferson Lab, Newport News, VA USA, 34Jefferson Lab, Newport News, VA USA, 35Jefferson Lab, Newport News, VA USA, 36Jefferson Lab, Newport News, VA USA, 37Jefferson Lab, Newport News, VA USA, 38Jefferson Lab, Newport News, VA USA, 39Jefferson Lab, Newport News, VA USA, 40Jefferson Lab, Newport News, VA USA, 41Jefferson Lab, Newport News, VA USA, 42Jefferson Lab, Newport News, VA USA, 43Jefferson Lab, Newport News, VA USA, 44Jefferson Lab, Newport News, VA USA, 45Jefferson Lab, Newport News, VA USA, 46Physics Dept. U.C. Berkeley, Berkeley, CA USA, 47Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD USA, 48Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD USA, 49Physics Department, Arizona State University, Tempe, 50Physics Department, Arizona State University, Tempe, 51Los Alamos National Laboratory, Los Alamos NM USA, 52Physics Dept., Hampton University, Hampton, VA and Jefferson Lab, Newport News, VA USA, 53Physics Dept., Hampton University, Hampton, VA and Jefferson Lab, Newport News, VA USA, 54Physics Dept., Hampton University, Hampton, VA and Jefferson Lab, Newport News, VA USA, 55Physics Dept., Catholic University of America, Washington, DC USA, 56Physics Dept., Catholic University of America, Washington, DC USA, 57Physics Dept., Catholic University of America, Washington, DC USA, 58Temple University, Philadelphia PA USA, 59Temple University, Philadelphia PA USA, 60Temple University, Philadelphia PA USA, 61Temple University, Philadelphia PA USA, 62Temple University, Philadelphia PA USA, 63University Bonn, Bonn Germany, 64University Bonn, Bonn Germany, 65University Bonn, Bonn Germany, 66Physikalisches Institut Justus-Liebig-Universitt Giessen, Giessen Germany, 67Physikalisches Institut Justus-Liebig-Universitt Giessen, Giessen Germany

We give a short overview of the DarkLight detector concept which is designed to search for a heavy photon A' with a mass in the range 10 MeV/c^2 < m(A') < 90 MeV/c^2 and which decays to lepton pairs. We describe the intended operating environment, the Jefferson Laboratory free electon laser, and a way to extend DarkLight's reach using A' --> invisible decays. Read More

2013May
Affiliations: 1Laboratory for Nuclear Science, Massachusetts Institute of Technology, 2Department of Physics, Arizona State University, 3Department of Physics, Arizona State University, 4Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 5Laboratory for Nuclear Science, Massachusetts Institute of Technology, 6Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 7Laboratory for Nuclear Science, Massachusetts Institute of Technology, 8Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 9Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 10Laboratory for Nuclear Science, Massachusetts Institute of Technology, 11Laboratory for Nuclear Science, Massachusetts Institute of Technology, 12Department of Physics, Hampton University, 13Laboratory for Nuclear Science, Massachusetts Institute of Technology, 14Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 15Laboratory for Nuclear Science, Massachusetts Institute of Technology, 16Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 17Laboratory for Nuclear Science, Massachusetts Institute of Technology, 18Laboratory for Nuclear Science, Massachusetts Institute of Technology, 19Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 20Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 21Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA

Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Read More

2013May
Affiliations: 1Department of Physics, Arizona State University, USA, 2Department of Physics, Arizona State University, USA, 3Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 4Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 5Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 6Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 7Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 8Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 9Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 10Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 11Department of Physics, Hampton University, VA USA, 12Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 13Department of Physics, College of William and Mary, Williamsburg, USA, 14Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 15Department of Physics, University of New Hampshire, USA, 16Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 17Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 18Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 19Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 20Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 21Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 22Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 23Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. Read More

High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration for this new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jefferson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Read More

Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer. Read More

As part of an experiment to measure the spectrum of photons emitted in beta-decay of the free neutron, we developed and operated a detector consisting of 12 bismuth germanate (BGO) crystals coupled to avalanche photodiodes (APDs). The detector was operated near liquid nitrogen temperature in the bore of a superconducting magnet and registered photons with energies from 5 keV to 1000 keV. To enlarge the detection range, we also directly detected soft X-rays with energies between 0. Read More

RESTful services on the Web expose information through retrievable resource representations that represent self-describing descriptions of resources, and through the way how these resources are interlinked through the hyperlinks that can be found in those representations. This basic design of RESTful services means that for extracting the most useful information from a service, it is necessary to understand a service's representations, which means both the semantics in terms of describing a resource, and also its semantics in terms of describing its linkage with other resources. Based on the Resource Linking Language (ReLL), this paper describes a framework for how RESTful services can be described, and how these descriptions can then be used to harvest information from these services. Read More

The roles played by mesons in the electromagnetic form factors of the nucleon are explored using as a basis a model containing vector mesons with coupling to the continuum together with the asymptotic $Q^2$ behavior of perturbative QCD. Specifically, the vector dominance model (GKex) developed by Lomon is employed, as it is known to be very successful in representing the existing high-quality data published to date. An analysis is made of the experimental uncertainties present when the differences between the GKex model and the data are expanded in orthonormal basis functions. Read More

The Nab collaboration will perform a precise measurement of 'a', the electron-neutrino correlation parameter, and 'b', the Fierz interference term in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS, using a novel electric/magnetic field spectrometer and detector design. The experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will provide an independent measurement of lambda = G_A/G_V, the ratio of axial-vector to vector coupling constants of the nucleon. Nab also plans to perform the first ever measurement of 'b' in neutron decay, which will provide an independent limit on the tensor weak coupling. Read More

2008Mar
Affiliations: 1corresponding author, 2corresponding author, 3corresponding author, 4corresponding author, 5corresponding author, 6corresponding author, 7corresponding author, 8corresponding author, 9corresponding author, 10corresponding author, 11corresponding author, 12corresponding author, 13corresponding author, 14corresponding author, 15corresponding author, 16corresponding author, 17corresponding author, 18corresponding author, 19corresponding author, 20corresponding author, 21corresponding author, 22corresponding author, 23corresponding author

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. Read More

We report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared $Q^2$ from 0.15 to 0. Read More

The mean square polarizability radii of the proton have been measured for the first time in a virtual Compton scattering experiment performed at the MIT-Bates out-of-plane scattering facility. Response functions and polarizabilities obtained from a dispersion analysis of the data at Q2=0.06 GeV2/c2 are in agreement with O(p3) heavy baryon chiral perturbation theory. Read More

2002Dec
Affiliations: 1OOPS Collaboration, 2OOPS Collaboration, 3OOPS Collaboration, 4OOPS Collaboration, 5OOPS Collaboration, 6OOPS Collaboration, 7OOPS Collaboration, 8OOPS Collaboration, 9OOPS Collaboration, 10OOPS Collaboration, 11OOPS Collaboration, 12OOPS Collaboration, 13OOPS Collaboration, 14OOPS Collaboration, 15OOPS Collaboration, 16OOPS Collaboration, 17OOPS Collaboration, 18OOPS Collaboration, 19OOPS Collaboration, 20OOPS Collaboration, 21OOPS Collaboration, 22OOPS Collaboration, 23OOPS Collaboration, 24OOPS Collaboration, 25OOPS Collaboration, 26OOPS Collaboration, 27OOPS Collaboration, 28OOPS Collaboration, 29OOPS Collaboration, 30OOPS Collaboration, 31OOPS Collaboration, 32OOPS Collaboration, 33OOPS Collaboration, 34OOPS Collaboration, 35OOPS Collaboration, 36OOPS Collaboration, 37OOPS Collaboration, 38OOPS Collaboration, 39OOPS Collaboration, 40OOPS Collaboration, 41OOPS Collaboration, 42OOPS Collaboration, 43OOPS Collaboration, 44OOPS Collaboration, 45OOPS Collaboration, 46OOPS Collaboration, 47OOPS Collaboration

Quadrupole amplitudes in the $\gamma^{*}N\to\Delta$ transition are associated with the issue of nucleon deformation. A search for these small amplitudes has been the focus of a series of measurements undertaken at Bates/MIT by the OOPS collaboration. We report on results from H$(e,e^\prime p)\pi^0$ data obtained at $Q^2= 0. Read More

We report on a measurement of spin-momentum correlations in quasi-elastic scattering of longitudinally polarized electrons with an energy of 720 MeV from vector-polarized deuterium. The spin correlation parameter $A^V_{ed}$ was measured for the $^2 \vec{\rm H}(\vec e,e^\prime p)n$ reaction for missing momenta up to 350 MeV/$c$ at a four-momentum transfer squared of 0.21 (GeV/c)$^2$. Read More

Measurements of the ${^2}H(\vec{e},e^{\prime}p)n$ reaction were performed using an 800-MeV polarized electron beam at the MIT-Bates Linear Accelerator and with the out-of-plane magnetic spectrometers (OOPS). The longitudinal-transverse, $f_{LT}$ and $f_{LT}^{\prime}$, and the transverse-transverse, $f_{TT}$, interference responses at a missing momentum of 210 MeV/c were simultaneously extracted in the dip region at Q$^2$=0.15 (GeV/c)$^2$. Read More

We report on the first measurement of spin-correlation parameters in quasifree electron scattering from vector-polarized deuterium. Polarized electrons were injected into an electron storage ring at a beam energy of 720 MeV. A Siberian snake was employed to preserve longitudinal polarization at the interaction point. Read More

We report on the first measurement of spin-correlation parameters in quasifree electron scattering from vector-polarized deuterium. Polarized electrons were injected into an electron storage ring at a beam energy of 720~MeV. A Siberian snake was employed to preserve longitudinal polarization at the interaction point. Read More

We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm$^{-1}$. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/$c$ with a tensor polarized $^2$H target internal to an electron storage ring. Read More

The coincidence cross-section and the interference structure function, R_LT, were measured for the 12C(e,e'p) 11B reaction at quasielastic kinematics and central momentum transfer of q=400 MeV/c. The measurement was at an opening angle of theta_pq=11 degrees, covering a range in missing energy of E_m = 0 to 65 MeV. The R_LT structure function is found to be consistent with zero for E_m > 50 MeV, confirming an earlier study which indicated that R_L vanishes in this region. Read More